1. Field of the Invention
The invention relates generally to television and, more particularly, to converting light signals from a film reel into a standard video signal format.
2. Description of Related Art
Cinema projectors for certain film formats, particularly 8 millimeter film, have not been manufactured since the 1980s. To date, the only options for replaying 8 millimeter film were to use projectors that had had more than 20 years pass since their manufacture or to pay a fee to a video conversion service to convert the film to a video or DVD format. Cinema projectors that are more than 20 years old tend to be aged and decrepit, most are likely to suffer from some malfunction and official support from the most manufacturers is no longer available. In short, even if a member of the general public possesses the film, they do not have any means of projecting the film when their projector breaks down.
Moreover, only high-priced commercial telecine equipment is available for converting the film into the video signal format, making it difficult to obtain substitute equipment for the film projectors.
Furthermore, none of the recording frame rates for film—there are various formats at 16, 18 or 24 frames per second—correspond to the frame rates for video signals (the NTSC format is 30 frames per second, the PAL and SECAM are 25 frames per second), making it useless to simply replace one film frame with one or two video signal frames.
Many formats that interpolate the difference between the film recording frame rate and video signal frame rates, many conversion formats and many telecine devices have been invented, but most of them are of a format that advances the film at fixed speeds and interpolates at the conversion to the video signal stage, and are made for commercial films that are larger in size than the 16 millimeter film recorded at 24 frames per second. For example, Japanese patent applications 2002-359775, 2002-77832 and 2001-103373 all use these methods. The 8 millimeter Film-Video Conversion Device filed under Japanese patent application 2005-252418 by the inventor of the current application provides for a telecine device that is smaller and cheaper than the commercial telecine devices, but it advances the film at a fixed speed and is no different from the devices that interpolate at the conversion to video signal stage. Thus, the processes that interpolate at the stage when the images are converted to a video signal cannot use standard video camera circuits without modification, making it necessary to develop specialized circuits and low-cost production is therefore limited.
Methods of converting the film images to video signals by controlling the film frame advancement have been proposed in such patent applications as Japanese patents Heisei-11-32255 and Heisei-10-126685, and they propose to raise image quality by synchronizing the film frame advancement with the video signal creation, but they do not play the film in real time and do not automatically interpolate the difference between the film recording frame rate and the video signal frame rate. Namely, they are not intended to create video signals from movie and other film in real time. To date, there has been no telecine device using the method of interpolating the difference between recording frame rates and video signal frame rates at the film frame advancement stage, and using standard video camera circuits without modification to convert to a video signal.